Reporters wait outside a Chengdu courthouse where former Chongqing police chief Wang Lijun is under trial.

The trial of former Chongqing police chief Wang Lijun started unexpectedly behind closed doors yesterday. Officials had earlier announced part of the case would be heard in open court today.

Wang, also the city's former vice-mayor and once the right-hand man of now-suspended Politburo member Bo Xilai , went on trial in Chengdu on two charges relating to state secrets, his defence lawyer Wang Yuncai said yesterday.

"Wang Lijun was charged with the crimes of defecting and of abusing power during Monday's trial, which was held behind closed doors," the lawyer said. The abuse-of-power charge relates to prosecutors' accusation that Wang Lijun made "unauthorised use of technical reconnaissance measures", which included forging official approval documents.

A spokesman for the Chengdu court had said earlier that part of Wang's trial would be conducted secretly, without giving a date.

The lawyer said she was present on Wang Lijun's behalf and that the four-hour hearing ended at around 12.30pm.

Asked whether Wang Lijun pleaded guilty yesterday, or if she entered a not-guilty plea on his behalf, Wang Yuncai, who is based in Shenyang in the northeast said: "Excuse me, but it is really inconvenient to talk about that at this stage."

Another hearing will begin today on two other charges relating to accusations that Wang Lijun manipulated the law for personal gain and took bribes, the lawyer said.

Wang Lijun, 52, fled to the US consulate in Chengdu in February and revealed that a British businessman had been murdered. This triggered the nation's biggest political scandal in decades, and saw the removal of Bo - then Chongqing's party chief - from the Communist Party leadership and the conviction of his wife for the murder.

Putting Wang on trial is the next step in the Communist Party leadership's effort to move beyond the scandal and deal with the stickier issue: whether to expel Bo from the party and prosecute him.

During the trial of Bo's wife, Gu Kailai , there was no mention of whether Bo was in any way linked to her case. Whether or not Bo's name is mentioned in today's open trial may shed some light on the party leadership's decision regarding his fate.

While today's trial is supposed to be open, it is expected that all the seats will be filled by selected members of the public, as was the case for Gu's trial.

A policeman for more than 20 years, Wang made a name for himself as a gang buster in Liaoning province in the northeast, where he met Bo, then a fast-rising politician who, as the son of a revolutionary veteran, had a web of political contacts.

The two rose to national fame together, launching a high-profile sweep against organised crime in Chongqing.

In a report on his indictment two weeks ago, Xinhua said that Wang knew Gu was suspected in the murder of British businessman Neil Heywood over a business dispute, but that Wang Lijun "neglected his duty and bent the law for personal gain" to cover up for Gu.

Additional reporting by Associated Press

This article appeared in the South China Morning Post print edition as Bo Xilai's former right-hand man goes on trial